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Finding the Fourth Proportional to 128.58, 191.81 and 123.99

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Solution

The fourth proportional to 128.58, 191.81 and 123.99 is: 184.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.58 : 191.81 = 123.99 : x
  2. Step 2: Convert to fraction form
    128.58/191.81 = 123.99/x
  3. Step 3: Cross multiply
    128.58x = 191.81 × 123.99
  4. Step 4: Simplify right side
    128.58x = 23,781.90
  5. Step 5: Solve for x
    x = 23,781.90/128.58
  6. Step 6: Final answer
    x = 184.96

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.